A squad of 300 National Guard troops landed in anarchic New Orleans fresh from Iraq on Thursday, with authorization to shoot and kill "hoodlums", Louisiana Governor Kathleen Blanco said.

"Three hundred of the Arkansas National Guard have landed in the city of New Orleans," said Blanco.

"These troops are fresh back from Iraq, well trained, experienced, battle tested and under my orders to restore order in the streets," Blanco said.

"They have M-16s and they are locked and loaded.

"These troops know how to shoot and kill and they are more than willing to do so if necessary and I expect they will," said Blanco.

Colonel Henry Whitehorn of the Louisiana State Police said that the law and order situation in the city was "bad."

He said however anarchic conditions around the Superdome stadium and central business district where up to 20,000 refugees have been sheltering had been "stabilising."

But he admitted that a number of police officers, who had lost everything in flooding after Hurricane Katrina which roared ashore last Monday, had handed in their badges, unwilling to take the fight to looters.